Stable carbon isotopes accurately predict diet selection by sheep fed mixtures of C3 annual pastures and saltbush or C4 perennial grasses

Norman, Hayley C.; Wilmot, M. G.; Thomas, Dean T.; Masters, David G.; Revell, Dean

doi:10.1016/j.livsci.2008.06.005

Cited by 44 publications

(63 citation statements)

References 35 publications

(69 reference statements)

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“…Plants that follow the C 3 photosynthetic pathway exhibit a higher level of carbon isotope fractionation than C 4 plants (Marshall and Zhang, 1994). The resulting difference in carbon isotope composition of the organic matter has been exploited to estimate the gross diet composition of herbivores in terms of the two plant groups (Coates et al, 1987;Norman et al, 2009). Differences in carbon isotope fractionation between species that follow the same photosynthetic pathway have also been documented (Ehleringer, 1991).…”

Section: Alkane Concentrationsmentioning

confidence: 99%

Evaluation of n-alkanes and their carbon isotope enrichments (δ13C) as diet composition markers

Bezabih

Pellikaan

Tolera

et al. 2011

Animal

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Plant cuticular n-alkanes have been successfully used as markers to estimate diet composition and intake of grazing herbivores. However, additional markers may be required under grazing conditions in botanically diverse vegetation. This study was conducted to describe the n-alkane profiles and the carbon isotope enrichment of n-alkanes of common plant species from the Mid Rift Valley rangelands of Ethiopia, and evaluate their potential use as nutritional markers. A total of 23 plant species were collected and analysed for long-chain n-alkanes ranging from heptacosane to hexatriacontane (C 27 to C 36 ), as well as their carbon isotopic ratio ( 13 C/ 12 C). The analysis was conducted by gas chromatography/combustion isotope ratio mass spectrometry following saponification, extraction and purification. The isotopic composition of the n-alkanes is reported in the delta notation (d 13 C) relative to the Vienna Pee Dee Belemnite standard. The dominant n-alkanes in the species were C 31 (mean 6 s.d., 283 6 246 mg/ kg dry matter) and C 33 (149 6 98 mg/kg dry matter). The carbon isotopic enrichment of the n-alkanes ranged from 219.37% to 237.40%. Principal component analysis was used to examine interspecies differences based on n-alkane profiles and the carbon isotopic enrichments of individual n-alkanes. Large variability among the pasture species was observed. The first three principal components explained most of the interspecies variances. Comparison of the principal component scores using orthogonal procrustes rotation indicated that about 0.84 of the interspecies variances explained by the two types of data sets were independent of each other, suggesting that the use of a combination of the two markers can improve diet composition estimations. It was concluded that, while the n-alkane profile of the pasture species remains a useful marker for use in the study region, the d 13 C values of n-alkanes can provide additional information in discriminating diet components of grazing animals.

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Section: Alkane Concentrationsmentioning

confidence: 99%

Evaluation of n-alkanes and their carbon isotope enrichments (δ13C) as diet composition markers

Bezabih

Pellikaan

Tolera

et al. 2011

Animal

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“…An alternative to this is to take advantage of the "sampling" activity of livestock which are grazing the grassland. Provided that they do not select between photosynthetic types, and eventual post-ingestion fractionation (possibly resulting from differential digestibility of C3 and C4 plants) of carbon isotopes is known, the δ 13 C of vegetation can be inferred from wool or other animal tissue (e.g., Jones et al, 1981;Schnyder et al, 2006;Norman et al, 2009). Geostatistical analysis can then be used to separate between the regional pattern and the noise of the individual samples, e.g.…”

Section: Introductionmentioning

confidence: 99%

Large regional-scale variation in C3/C4 distribution pattern of Inner Mongolia steppe is revealed by grazer wool carbon isotope composition

Auerswald¹,

Wittmer²,

Männel³

et al. 2009

Biogeosciences

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Abstract. This work explored the spatial variation of C3/C4 distribution in the Inner Mongolia, P. R. China, steppe by geostatistical analysis of carbon isotope data of vegetation and sheep wool. Standing community biomass (n=118) and sheep wool (n=146) were sampled in a ∼0.2 Mio km 2 area. Samples from ten consecutive years (1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007) were obtained. Community biomass samples represented the carbon isotopic composition of standing vegetation on about 1000 m 2 ("community-scale"), whereas the spatio-temporal scale of wool reflected the isotope composition of the entire area grazed by the herd during a 1-yr period (∼5-10 km 2 , "farm-scale"). Pair wise sampling of wool and vegetation revealed a 13 C-enrichment of 2.7±0.7‰ (95% confidence interval) in wool relative to vegetation, but this shift exhibited no apparent relationships with environmental parameters or stocking rate. The proportion of C4 plants in aboveground biomass (P C4 , %) was estimated with a two-member mixing model of 13 C discrimination by C3 and C4 vegetation ( 13 3 and 13 4 , respectively), in accounting for the effects of changing 13 C in atmospheric CO 2 on sample isotope composition, and of altitude and aridity on 13 3 . P C4 averaged 19%, but the variation was enormous: full-scale (0% to 100%) at community-scale, and 0% to 85% at farm-scale. The farm-scale variation of P C4 exhibited a clear regional pattern over a range of ∼250 km. Importantly P C4 was significantly higher above the 22 • C isotherm of the warmest month, which was obtained from annual high-resolution Correspondence to: K. Auerswald (auerswald@wzw.tum.de) maps and averaged over the different sampling years. This is consistent with predictions from C3/C4 crossover temperature of quantum yield or light use efficiency in C3 and C4 plants. Still, temperature gradients accounted for only 10% of the farm-scale variation of P C4 , indicating that additional factors control P C4 on this scale.

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“…Infrared light intensity diminishes to a greater extent than far-infrared when light is filtered through the plant canopy, thus removal of the upper plant canopy by grazing will increase the infrared/far-infrared ratio of the light reaching the short grasses, and will enhance the tillering of C. squarrosa. The last and perhaps the most important reason is the differences in the preference (McPherson and Rasmussen 1989) and digestibility (Norman et al 2009) of the C 3 and C 4 species. Yokohama et al (2011) Norman et al (2009) indicated that the C 4 species in the region have lower digestibility values than C 3 species and so the grazing livestock tend to prefer the C 3 species.…”

Section: Both Temperature and Grazing Can Promote The Abundance Of C mentioning

confidence: 99%

“…The last and perhaps the most important reason is the differences in the preference (McPherson and Rasmussen 1989) and digestibility (Norman et al 2009) of the C 3 and C 4 species. Yokohama et al (2011) Norman et al (2009) indicated that the C 4 species in the region have lower digestibility values than C 3 species and so the grazing livestock tend to prefer the C 3 species.…”

Section: Both Temperature and Grazing Can Promote The Abundance Of C mentioning

confidence: 99%

“…Firstly, grazing may have changed the micro-environment. Secondly, the foraging preferences of herbivores caused by the different palatability of C 3 and C 4 plants (McPherson and Rasmussen 1989), as well as differences in their digestibility could mean that the animals select either C 3 or C 4 plants (Whalley 1994;Norman et al 2009). However, other studies suggested that grazing had no effects on the relative abundance of C 4 plants (Derner et al 2006;Auerswald et al 2012).…”

Section: Introductionmentioning

confidence: 99%

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Grazing primarily drives the relative abundance change of C4 plants in the typical steppe grasslands across households at a regional scale

Zhang

Ding

et al. 2014

Rangel. J.

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Abstract. Increases in temperature and grazing intensity are believed to promote the relative abundance of C 4 plants in grassland communities in Inner Mongolia. However, there is a lack of understanding as to which factor is the primary driver at the household scale. The relative abundance of C 4 plants in grassland communities within 32 households was monitored over a 5-year period in the typical steppe region of Inner Mongolia. The relationships between the mean annual temperature, grazing intensity and their combinations on the patterns of the relative abundance of C 4 plants across the land managed by these households were analysed. The results showed that (1) the herbage mass of the typical steppe grassland was mainly composed of C 3 plants (87%); (2) the C 4 plants were more sensitive to, and can be used as indicators of, environmental changes. These C 4 species included Cleistogenes squarrosa (Trin.) Keng, Chenopodium glaucum Linn. and Salsola collina Pall.; (3) both increasing temperature and grazing intensity promoted the relative abundance of C 4 plants. Grazing intensity was the primary driver of the change in relative abundance of C 4 plants in this region. Not only did grazing change the micro-environment of the grasslands, but also the C 3 species were preferentially grazed by the livestock. Comparison of the results with previous studies on the temporal variation in the abundance of C 4 plants suggests that the relative importance of grazing and climatic factors depends on the spatial scales of the studies, with climate being of greater importance at the regional rather than the household scale.

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Stable carbon isotopes accurately predict diet selection by sheep fed mixtures of C3 annual pastures and saltbush or C4 perennial grasses

Cited by 44 publications

References 35 publications

Evaluation of n-alkanes and their carbon isotope enrichments (δ13C) as diet composition markers

Evaluation of n-alkanes and their carbon isotope enrichments (δ13C) as diet composition markers

Large regional-scale variation in C3/C4 distribution pattern of Inner Mongolia steppe is revealed by grazer wool carbon isotope composition

Grazing primarily drives the relative abundance change of C4 plants in the typical steppe grasslands across households at a regional scale

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